Fortification of food products with olive fruit ingredients

ABSTRACT

Method of fortification of a food product with olive fruit ingredients, particularly phenolic compounds by adding solid matter derived from non-debittered olive fruit to the food product.

The present invention relates to a method of fortifying food productswith olive fruit ingredients. According to this method solid matterderived from olive fruit is added to food products, which results in anincrease of the level of anti-oxidants, particularly of olivepolyphenols.

BACKGROUND OF THE INVENTION

The incidence of cardiovascular diseases in a population is correlatedwith the occurrence of a high blood cholesterol content. The bloodcholesterol level has been found to be decreased by a diet, whichcontains specific food components. For example, it is recommended to eatfats with a high content of unsaturated fatty acids.

It is known further that particularly diets which contain olive oil arehealthy, because olive oil consumption contributes to a good balance ofHDL cholesterol and LDL cholesterol in the blood. Recently it has beenfound that some minor fat components particularly the anti-oxidants,including polyphenols from fat, positively interfere with the body'scardiovascular system, particularly because they are believed to helpcontrol oxidation of blood cholesterol. Non-refined olive oil has a highcontent of phenolic compounds which often are denoted as phenolics,polyphenols or, specifically, as olive phenolics or as olive polyphenols

Copending WO 99/32589 describes a useful application of said finding.The invention relates to spreads which contain olive oil as well asphenolic compounds. Traditionally for spread preparation an olive oil isemployed which has been fully refined. The refining has removed togetherwith the impurities also the beneficial phenolic compounds. Said patentapplication describes a refining process which is so mild that itdelivers a purified oil from which undesired olive oil odour and most ofthe free fatty acids have been removed, but which still contains aconsiderable amount of healthy phenolic compounds.

The phenolics derived from olives form a group of chemical compounds,some of which have a relatively high oil solubility, the lipophilicolive phenolics, while others are more soluble in water, the hydrophilicolive phenolics. Only recently attention is given to the nutritionalbenefits of the hydrophilic polyphenols.

When olive oil is contacted with a water phase, e.g. during the usualwater washing step, a partitioning of phenolic compounds occurs. A greatpart of the phenolic compounds is so hydrophilic that they easilymigrate to the water phase, while the major part of the lipophilicphenolic compounds stay in the oil phase.

At least a part of the bitter taste of olive oil is ascribed to phenoliccompounds. The lipophilic phenolic compounds which occur in the oliveoil most contribute to the bitter taste.

In co-pending patent applications EP 849353 and EP 933419 olive oilprocesses are described, which aim at debittering the olive oil byremoving and/or hydrolysing lipophilic phenolic compounds in olive oil.By hydrolysis the bitter lipophilic phenolic compounds are convertedinto the less bitter and more water soluble phenolic compounds. Sincemost of these migrate to the water phase of the olive oil/water mixture,they are removed when the separated water phase is discarded.

A characteristic sensoric property of many non-refined olive oils isastringency. The astringency is perceived as a non-pleasant feelinglingering in the back of the throat after some oil has been ingested.Excessive astringency, like excessive bitterness, spoils the taste ofthe oil. Astringency in olive oil appears to increase with its contentof polyphenols.

WO 97/06697 teaches a healthy diet consisting of food products whichhave been fortified with high amounts of anti-oxidants, includingphenolic compounds.

According to JP 59213368 (Derwent abstract) a tasty spread or cream isobtained by adding finely ground olives to food containing a fat-richfood ingredient. Because of the known astringent and bitter taste ofolives, the olives are used only after a debittering treatment withsodium hydroxide solution.

It is known that after a sodium hydroxide treatment olives aresubstantially depleted with polyphenols. Therefore said process is notsuited to enhance the content of phenolic compounds in a food product.

The aim of the present invention is to enhance the nutritional value ofa food product by the addition of solid ingredients derived from olivefruits. Particularly vegetable oils, spreads, mayonnaises, saladdressings and sauces, in particular tomato sauces, may benefit from theinvention. Particularly, the object of the present invention is toenrich food products with polyphenols from olive fruits.

SUMMARY OF THE INVENTION

It has been found that the solids of the olive fruit form a greatresource of phenolic compounds. While the occurrence of those compoundsin olive oil is about 200 ppm, in the water phase of olives it is 5000ppm and in the solid remains even 10,000 ppm.

The invention is based on the finding that the solid matter ofnon-debittered olive fruits has appeared to be suited for enhancing thenutritional value of food products.

The aim of enhancing the nutritional value of a food product byfortification with useful olive fruit ingredients, is attained byincorporating into the food product solid matter derived from oliveswhich solid matter has a particle size of 0.1 μm-5 mm, however, with theproviso that the used olives must not have been subjected to the usualdebittering treatment.

Particularly, the invention provides a method to increase in foodproducts the content of anti-oxidants, particularly the content of olivephenolics.

The invention further comprises a vegetable oil with a content of atleast 180 ppm of olive phenolics, which oil comprises a dispersion of0.05-0.5 wt. % of solid matter derived of olive fruit with a particlesize of 0.1 μm-5 mm. At least 18 ppm of the olive phenolics isassociated with said particles and is removed by filtration of the oil.

DESCRIPTION OF FIG

The graph of FIG. 1 shows the relation of standard solutions of bitteroleuropein in refined olive oil and bitterness score. In this way it ispossible to assess bitterness by comparison the taste of an oil with thetaste of oleuropein solutions.

DETAILS OF THE INVENTION

The present invention uses solid matter derived from olive fruits. Suchmatter is chosen from the group consisting of 1. particles obtained bydiminuting unprocessed olives, 2. the solids which settle at the bottomof tanks in which the oil resulting from olives pressing is stored and3. particles of the cake which remains after pressing the liquid phasefrom olives. Said solid matter contains high concentrations of olivephenolics.

Preferably the kernels are left out from the solid matter. Suited forthe present invention is only solid matter obtained from olives whichhave not been subjected to a debittering treatment.

Preferably, the solid olive matter is added to the food product in anamount of 0.05-0.5 wt. %, preferably 0.1-0.3 wt. %.

Wt. % is calculated as dry weight on total food product.

The olive derived solid matter can be obtained by simply cuttingharvested olives in pieces, or by other well known methods for choppingand diminuting olive fruits. A high shear mixer, such as anUltra-turrax™ can be used for further reducing the size of the oliveparticles. Preferably, the particle size is such that the olive fruitsolid matter does not settle when dispersed in a vegetable oil. Theparticle size suitably is in the range 0.1 μm-5 mm, preferably 0.1μm-0.1 mm.

For obtaining a fortified food product which normally contains avegetable oil, that oil can suitably be replaced by a vegetable oilenriched according to the present invention.

According to one embodiment of the invention the olive solid matter issimply added as an ingredient of the final food product.

According to another embodiment of the invention the olive derived solidmatter is allowed to soak in vegetable oil for at least one minute andthen the solid matter is separated from the oil. A part of the usefulingredients in the solid matter will dissolve during soaking and a partwill remain associated with the solid particles.

Preferably, the soaking proceeds for at least 10 minutes, morepreferably for at least one hour and even more preferably for at leastone day. In a specific production process some trials will easilyindicate which soaking time delivers the desired fortification. Thisseparation embodiment is preferred only when a clear product is desired.Together with the solid matter also chose useful olive ingredients whichare associated with chat solid matter are removed.

The temperature of the oil during soaking the solid matter is suitablykept at 30°-300° C. Relatively low temperatures are preferred. Soakingwith a heated oil will accelerate the fortification process and also mayincrease the final concentration of the beneficial ingredients of theolive fruits which have migrated into the oil. The particles are removedpreferably before the oil has cooled to ambient temperature. For removalone can use filtration, centrifugation or decantation.

The beneficial polyphenols known to be present in olive fruits are amixture of different compounds which share the property of having one ormore phenolic hydroxyl groups. The main polyphenols originating fromolive fruit comprise oleuropein, aglycon, tyrosol and hydroxytyrosol.

The food products fortified according to the present invention containat least 10 ppm, preferably at least 50 ppm, more preferably at least200 ppm of olive originating polyphenols.

According to another aspect of the present invention it is also possibleto start with a blend of different types of olive fruits. A properchoice enables the adjustment of levels and types of beneficial oliveingredients, as well as of the taste of the obtained food products.

Olives harvested in the begin phase of their ripening are at theirmaximum polyphenols content. Use of those olives can enhance stillfurther the fortification with phenolic compounds. Use of green olivesusually gives the best results. The olive fruits may be processeddirectly after harvesting. But it is also possible to freeze-dry theolives and store them for later processing.

The present invention also comprises novel vegetable oils characterizedby the presence of 0.05-0.5 wt. % of olive derived solid matter and atleast 180 ppm of olive phenolic compounds. The oils of the presentinvention are characterized further in that an amount of at least 18 ppmof those phenolic compounds is associated with the solid matter.Association means that removal, e.g. by filtration, of the solid matterfrom the oil lowers the overall content of phenolics in the oilassociated with those solids.

The substantial increase of beneficial components from the olive fruits,particularly an increase of polyphenols, results into a change ofvarious oil properties such as the oxidation stability of the oil. TheRancimat™ test is a common and simple standard test for establishing theinduction time which is a measure for the oxidation stability of edibleoil.

As will be shown in the examples and contrary to expectation, additionof solid matter of non-debittered olive fruits in the claimed amounts tofood products hardly or not deteriorates the taste. Particularlyfortified olive oil exhibits a mild and often fruity, but hardly bitteraftertaste. Astringency, which is expected because of the increasedcontent of phenolic compounds, is hardly noticed or only at high levelsof phenolics. In olive oils not only a deterioration of the taste of theoil fails to turn up, often even an improvement of the taste may result.Possibly, the surprising impact on flavour may be ascribed, at leastpartially, to absorption of off-flavour causing components to the addedsolid matter of the olive.

Bitterness of olive oil can be assessed by comparing with standardsolutions of the phenolic compound oleuropein. The bitterness of asolution of oleuropein in refined olive oil increases proportionallywith concentration. The graph of FIG. 1 shows the relation ofconcentration and bitterness score. A bitterness score of 3 and higheris quite normal for a common non-refined olive oil which contains 180ppm of olive polyphenols. It is surprising that the bitterness score ofthe invented oils is less than 3, although they contain at least 180 ppmof olive oil polyphenols.

The bitterness score of a common non-refined olive oil 30 with apolyphenols content surpassing 300 ppm is at least 5.

The invention provides novel vegetable oils including olive oil whichcontain 0.05-0.5 wt. % of olive fruit derived solid matter, have apolyphenols concentration of at least 300 ppm, but, nevertheless,exhibit a bitterness score which is less than 5.

The invented method is suitable for fortifying vegetable oils such asrapeseed oil, sunflower seed oil, soybean oil, corn oil and, preferably,olive oil, which contain or not contain any amount of nativepolyphenols. Olive oil is comprised in all its quality grades: extravirgin olive oil, fine virgin olive oil, semi-fine or regular virginolive oil, refined virgin olive oil, such as Lampante oil, olive residueoil and also olive oil blends, which contain virgin olive oil as well asrefined olive oil. It should be noted that the solid olive matter to beused in the invention consists of natural olive ingredients.

It goes without saying that the invention also might be advantageous forthe fortification of fat blends which partly consist of fat derived fromanimals or marine organisms.

The method of the invention is further applicable for the fortificationof food products different from fat and oils, such as spreads, saladdressings, mayonnaise or a sauces.

In the present context spreads are understood to be food compositionswhich usually contain a substantial amount of fat emulsified with awater phase and which have a plastic consistency suitable for spreadingon bread. Usually the fat phase consists of a liquid oil and astructuring fat which gives the spread its desired plastic consistency.

Sauces include any type of sauce, such as sauces that are ready to useand tomato sauces. Processes for the manufacture of spreads and saucesare well known in the art and need no illustration.

Although the present invention relates to methods which use solid matterof olive fruits which are non-debittered, for culinary purposesdebittered olives may be used in addition when preparing the productscovered by the present invention.

For establishing polyphenol concentrations in the products of thepresent patent specification the colorimetric Gutfinger method has beenused. Since long the content of polyphenols in olive oils is establishedby this standard method. It is described in J. Am. Oil. Chem. Soc. 1981,11, pp. 966-968. The measurement is based on the reaction of amethanolic extract of olive oil and the Folin-Ciocalteau reagent.

Unless specified otherwise, the weight percentages of the solid matterparticles throughout this specification are calculated as dry weight ontotal food product.

In this specification the term fat comprises oil as well. The term oilis generally used when the fat is liquid at ambient temperature.

The invention is illustrated by the following examples.

General Rancimat™ Test

Through the heated oil of which the oxidation stability is to be testedair is bubbled. The Rancimat™ value is the induction time, the maximumtime during which no off-flavours can be smelled in the air which haspassed through the oil.

EXAMPLE 1

Two types of Italian olives of which the kernel had been removed, werechopped by means of an Ultra-turrax™ until a particle size of 100 μm.The chopped olives were added to a French and to a Greek extra-virginolive oil. After 24 hours of soaking the obtained turbid oils wereassessed on taste. The polyphenol content and the induction time weremeasured. See Tables I-IV for results.

EXAMPLE 2

This example was carried out in the same way as example 1, with theexception that freeze dried olives were chopped before addition to theoil and chat small particles are compared with larger particles. Fromthe figures in Tables V and VI it appears that a freeze drying treatmentenhances the migration of phenolic compounds into the oil.

The same effect is obtained when smaller particles are used.

TABLE I ITALIAN OLIVES TYPE 1 SOAKED IN FRENCH EXTRA VIRGIN OLIVE OILolives pp IT bitter score added ppm hours taste of the wt. % (1) (2)mixture 0 158 7.12 2, mild and (ref) fruity 0.4 175 6.13 not assessed0.5 187 6.05 2, less fruity, little aftertaste 0.67 235 — 2, bit fruity,mild aftertaste (1) PP = total polyphenol content (ppm) (2) IT =induction time (hours)

TABLE II ITALIAN OLIVES TYPE 2 IN FRENCH EXTRA VIRGIN OLIVE OIL olivesPP IT added ppm hours bitterness score wt. % (1) (2) taste of themixture 0 158 7.12 2, mild and fruity (ref.) 0.4 186 7.20 not assessed0.5 203 7.68 2, stronger taste, less fruity

TABLE III ITALIAN OLIVES TYPE 1 IN GREEK EXTRA VIRGIN OLIVE OIL olivesPP IT added ppm hours bitterness score wt. % (1) (2) taste of themixture 0 ref 147 3.00 2, bit fruity, strong taste 0.4 155 3.18 notassessed 0.5 183 3.82 2, not bitter, bit stronger (1) PP = totalpolyphenol content (ppm) (2) IT = induction time (hours)

TABLE IV ITALIAN OLIVES TYPE 2 IN GREEK EXTRA VIRGIN OLIVE OIL Olives PPIT Bitterness added (pp) hours score, Taste wt. % (1) (2) of the mixture0 ref 147 3.00 2, bit fruity strong taste 0.4 153 3.15 not assessed 0.5181 3.70 2, little astringency, little aftertaste (1) PP = totalpolyphenol content (ppm) (2) IT = induction time (hours)

TABLE V ITALIAN OLIVES TYPE 2 IN GREEK EXTRA VIRGIN OLIVE OIL bitternessolives PP IT score, taste added¹ (ppm) hours of the mixture 0 145 3.002, little aftertaste 2.5 320 4.68 3, mild, bit fruity ¹Wt. % bigparticles, particle size approximately 1 mm.

TABLE VI ITALIAN OLIVES TYPE 1 IN GREEK EXTRA VIRGIN OLIVE OILbitterness olives PP IT score, taste added² (ppm) hours of the mixture 0145 3.00 2, little aftertaste 2.5 532 6.72 3, mild, not bitter ²Wt. %small particles, size approximately 50 μm.

1. A method of fortifying a food product with phenolic compoundscomprising incorporating into the food product solid matter derived fromolives which have not been subjected to a debittering treatment, whichsolid matter has a particle size of 0.1 μm-5 mm, characterized in thatthe olives derived solid matter is added to the food product.
 2. Themethod according to claim 1, whereby the solid matter is chosen from thegroup consisting of
 1. Particles of unprocessed olive,
 2. The solidswhich settle at the bottom of tanks in which the oil resulting fromolives pressing is stored, and
 3. Particles of the cake which remainsafter pressing the liquid phase from olives.
 3. The method according toclaim 1, whereby the obtained food product contains at least 10 ppm ofolive derived phenolic compounds.
 4. The method according to claim 1,whereby the food product is a vegetable oil.
 5. A food product preparedwith the oil obtainable by the method according to claim
 4. 6. Themethod according to claim 1, whereby the olive solid matter is allowedto soak in the oil for at least one minute and then separating the solidfrom the oil.
 7. The method according to claim 1, whereby the foodproduct is chosen from a group consisting of a spread, a salad dressing,mayonnaise or a sauce.
 8. A food product obtainable by the methodaccording to claim 1.